Bought used at 35k mi, now have 48k mi. I drive my M3 daily mostly city on the weekdays and occasional highway on the weekends. Since then I've had to replace a battery, driver side mirror slightly discolored on the edge and when it's really cold the passenger side door doesn't unlock on the first try. Besides that the car has been very reliable, even after being to a couple of weekend track events. The only casualties being the tires, brakes and fuel. Great track car that you won't feel guilty driving everyday. Service is expensive, quoted $2k for Inspection II at the dealer, but did myself with $500 in parts. Inspection II is every 35k mi or so.
Steering feel is the benchmark of all sports cars. The handling is excellent and power is plentiful & smooth. At hard accel the exhaust note is just music. Good trunk space & mileage. It's a driver's car that not everyone will appreciate but for the few it's just what we're looking for.
If you don't work on cars, it'll get a little expensive for upkeep. Ride is really rough on bad roads, got adj coilovers to smooth it out on commutes, helps a lot wish I had done earlier. HK sound is just okay, seats are not good for long drives. All goes away on smooth twisty roads.
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